WASHINGTON, Jan 15 (Reuters) - The U.S. Senate voted on Tuesday to move ahead with a resolution disapproving of a Trump administration plan to ease sanctions on Russian aluminum giant Rusal, its parent En+ and power firm EuroSibEnergo.

While the vote did not determine the fate in the Senate of the resolution, it broke with Republican President Donald Trump by paving the way for debate on the plan the Treasury Department announced in December to ease sanctions on the companies after Russian oligarch Oleg Deripaska agreed to lower his controlling stake in the firm. (Reporting by Patricia Zengerle; editing by Grant McCool)